Metal ingots, billets and other castparts may be formed by a casting process, which utilizes a vertically oriented mold situated above a large casting pit beneath the floor level of the metal casting facility, although this invention may also be utilized in horizontal molds. The lower component of the vertical casting mold is a starting block. When the casting process begins, the starting blocks are in their upward-most position and in the molds. As molten metal is poured into the mold bore or cavity and cooled (typically by water), the starting block is slowly lowered at a pre-determined rate by a hydraulic cylinder or other device. As the starting block is lowered, solidified metal or aluminum emerges from the bottom of the mold and ingots, rounds or billets of various geometries are formed, which may also be referred to herein as castparts.
While the invention applies to the casting of metals in general, including without limitation aluminum, brass, lead, zinc, magnesium, copper, steel, etc., the examples given and preferred embodiment disclosed may be directed to aluminum, and therefore the term aluminum or molten metal may be used throughout for consistency even though the invention applies more generally to metals.
While there are numerous ways to achieve and configure a vertical casting arrangement, FIG. 1 illustrates one example. In FIG. 1, the vertical casting of aluminum generally occurs beneath the elevation level of the factory floor in a casting pit. Directly beneath the casting pit floor 101a is a caisson 103, in which the hydraulic cylinder barrel 102 for the hydraulic cylinder is placed.
As shown in FIG. 1, the components of the lower portion of a typical vertical aluminum casting apparatus, shown within a casting pit 101 and a caisson 103, are a hydraulic cylinder barrel 102, a ram 106, a mounting base housing 105, a platen 107 and a starting block base 108 (also referred to as a starting head or bottom block), all shown at elevations below the casting facility floor 104.
The mounting base housing 105 is mounted to the floor 101a of the casting pit 101, below which is the caisson 103. The caisson 103 is defined by its side walls 103b and its floor 103a. 
A typical mold table assembly 110 is also shown in FIG. 1, which can be tilted as shown by hydraulic cylinder 111 pushing mold table tilt arm 110a such that it pivots about point 112 and thereby raises and rotates the main casting frame assembly, as shown in FIG. 1. There are also mold table carriages which allow the mold table assemblies to be moved to and from the casting position above the casting pit.
FIG. 1 further shows the platen 107 and starting block base 108 partially descended into the casting pit 101 with castpart or billet 113 being partially formed. Ingot 113 is on the starting block base 108, which may include a starting head or bottom block, which usually (but not always) sits on the starting block base 108, all of which is known in the art and need not therefore be shown or described in greater detail. While the term starting block is used for item 108, it should be noted that the terms bottom block and starting head are also used in the industry to refer to item 108, bottom block typically used when an ingot is being cast and starting head when a billet is being cast.
While the starting block base 108 in FIG. 1 only shows one starting block 108 and pedestal 115, there are typically several of each mounted on each starting block base, which simultaneously cast billets, special shapes or ingots as the starting block is lowered during the casting process.
When hydraulic fluid is introduced into the hydraulic cylinder at sufficient pressure, the ram 106, and consequently the starting block 108, are raised to the desired elevation start level for the casting process, which is when the starting blocks are within the mold table assembly 110.
The lowering of the starting block 108 is accomplished by metering the hydraulic fluid from the cylinder at a pre-determined rate, thereby lowering the ram 106 and consequently the starting block at a pre-determined and controlled rate. The mold is controllably cooled during the process to assist in the solidification of the emerging ingots or billets, typically using water cooling means.
There are numerous mold and casting technologies that fit into mold tables, and no one in particular is required to practice the various embodiments of this invention, since they are known by those of ordinary skill in the art.
The upper side of the typical mold table operatively connects to, or interacts with, the metal distribution system. The typical mold table also operatively connects to the molds which it houses.
When metal is cast using a continuous cast vertical mold, the molten metal is cooled in the mold and continuously emerges from the lower end of the mold as the starting block base is lowered. The emerging billet, ingot or other configuration is intended to be sufficiently solidified such that it maintains its desired shape. There is an air gap between the emerging solidified metal and the permeable ring wall. Below that, there is also a mold air cavity between the emerging solidified metal and the lower portion of the mold and related equipment.
After a particular cast is completed, as described above, the mold table is typically tilted upward and away from the top of the casting pit, as shown in FIG. 1. When the mold table is tilted or pivoted, and without a lubricant control system, the lubricant tends to drain out of the conduits and leaks either into the casting pit or on the floor of the casting facility.
The use of a permeable or porous perimeter wall has proven to be an effective and efficient way to distribute lubricant and gas to the inside surface of a continuous casting mold, such as is described in U.S. Pat. No. 4,598,763 to Wagstaff, which is hereby incorporated herein by this reference as though fully set forth herein.
In the typical use of a permeable perimeter wall, lubricant and gas are delivered to the perimeter wall under pressure through grooves or delivery conduits around the perimeter wall, typically using one delivery conduit (if grooves are used for the delivery of lubricant) and one or two delivery conduits (grooves) for the delivery of gas. The preferred lubricants are synthetic oils, whereas the current preferred gas is air. The lubricant and gas then permeate through the perimeter wall and are delivered to the interior of the mold as part of the casting process.
The perimeter walls on existing mold tables each have delivery conduits to deliver the lubricant and/or gas, and the delivery conduits may be circumferential groove-shaped delivery conduits with the same depth and width, or they may be holes partially drilled through the perimeter walls, or any other delivery means for that matter. The typical perimeter wall has a separate lubricant delivery conduit and a gas conduit.
Although this invention is not limited to graphite, graphite has proven to be the preferred permeable material for use as the perimeter wall material or media. However, graphite has proven to be expensive in consistently producing high quality individual products which have very similar permeability to other graphite perimeter walls.
Prior to this invention, achieving the same flow rate or delivery rate of lubricant and/or gas flow through the entire perimeter of the perimeter walls is not being achieved to the degree desired, and this may result in a less desirable castpart and waste.
From a practical and expense perspective, lubricant and/or gas are supplied at a constant pressure, and the perimeter walls are manufactured at a constant or fixed thickness and general size to fit within the molds. The inner and outer diameters of the perimeter walls, as well as their overall height also is generally fixed.
It is an objective of this invention to provide a more even flow of lubricant through more of the perimeter wall, and preferably through the entire perimeter wall.
This invention accomplishes this and other objectives by providing a system for providing an improved lubricant flow groove configuration substantially around the entire permeable perimeter wall to allow the lubricant to permeate through the permeable perimeter wall and toward the mold cavity.
Other objects, features, and advantages of this invention will appear from the specification, claims, and accompanying drawings which form a part hereof. In carrying out the objects of this invention, it is to be understood that its essential features are susceptible to change in design and structural arrangement, with only one practical, and preferred embodiment being illustrated in the accompanying drawings, as required.